Ultra-lightweight Thin Film of Two-Dimensional Heterogeneous Materials for EMI Shielding

Abstract

The two-dimensional (2D) materials with excellent flexibility, having a light weight, and a high electrical conductivity can be a good candidate for electromagnetic interference (EMI) shielding in next-generation portable and wearable electronic devices. The novel properties of MXene (transition metal carbides, nitrides, or carbonitrides), have unique inherent features such as good electrical conductivity, 2D sheet shape, lightweight, flexibility, customizable surface chemistry, and facile solution processability. However, applying thin films made of Ti3C2Tx, a kind of Mxene, for EMI shielding is challenging because they are prone to chemical deterioration due to oxidation to TiO2. In this work, a heterogeneous 2D film of Ti3C2Tx MXene integrated with molybdenum disulfide (MoS2) and multiwalled carbon nanotube (MWCNT) (MWCNT@MoS2/MXene) with an ultrathin thickness was developed and it has proven to improve electromagnetic wave absorption (EMWs). Moreover, the oxidation of Ti3C2Tx and MWCNT@MoS2/MXene thin films was examined, for prolonged period of 35 days, under three distinct environmental conditions: in a dry box, at room temperature, and in an environmental chamber with 90% RH. EMI shielding effectiveness measurements were carried out to assess the performance of Ti3C2Tx MXenes and MWCNT@MoS2/MXene thin film under these environmental influences. Scanning electron microscopy (SEM) was used to evaluate the morphology while X-ray Diffraction was used to verify that the interplanar distance between the MXene sheets and the composite films. The MWCNT@MoS2/MXene ultrathin film had improved EMWs absorption, which was an important portion of shielding effectiveness (51 dB) as well as outstanding mechanical stability compared to Ti3C2Tx MXene film. In addition, the environmental stability of Ti3C2Tx Mxene was enhanced by integrating with MWCNT@MoS2. As a result, the engineered hetero-structure of multilayered hybrid films could be a promising choice for improved EMI shielding effectiveness and stability of pure MXene.

Date of Award	May 2022
Original language	American English